Machine and method for inflating and sealing air-filled packing cushions

ABSTRACT

Machine and method for making air-filled packing cushions from a roll of prefabricated film material having a longitudinally extending inflation channel near one edge of the material and chambers which communicate with the channel through laterally extending passageways. The roll rests on a pair of spaced apart, horizontally extending rollers. The film material is fed from the roll to an inflation tube which extends into the inflation channel, air is introduced into the chambers through the inflation tube to inflate the cushions, and a longitudinally extending seal is formed across the passageways between the channel and the chambers after the cushions are inflated.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention pertains generally to packing materials and, moreparticularly, to a machine and method for making air-filled packingcushions.

2. Related Art

Air-filled pillows or cushions are currently used as a packing materialand void filler in shipping cartons and the like. Such cushionstypically have two layers of plastic film material which are sealedtogether to form chambers that are filled with air. The cushions areusually made in continuous strings, with perforations between successiveones of the cushions so they can be torn apart.

Although very light in weight, air-filled cushions do take up asubstantial amount of space, and to reduce the volume of material whichmust be shipped and stored, such cushions are commonly made at or nearthe point of use. To avoid the need for packers and shippers to havelarge, complex cushion making machines in their facilities, suppliers ofair-filled packing cushions provide their customers with prefabricatedfilm materials in which the major seals and perforations have alreadybeen formed. Those materials usually wound into rolls or folded intoboxes for shipment and storage.

Packers and shippers who use the prefabricated film materials are alsoprovided with relatively simple, inexpensive machines for inflating andsealing the materials to complete the cushions at or near the point ofuse. Examples of such machines are found in U.S. Pat. No. 6,209,286 andin copending Ser. Nos. 09/638,843 and 09/717,782, the disclosures ofwhich are incorporated herein by reference.

OBJECTS AND SUMMARY OF THE INVENTION

It is in general an object of the invention to provide a new andimproved machine and method for making air-filled packing cushions.

Another object of the invention is to provide a machine and method ofthe above character which overcome the limitations and disadvantages ofthe prior art.

These and other objects are achieved in accordance with the invention byproviding a machine and method for making air-filled packing cushionsfrom a roll of prefabricated film material having two layers which aresealed together to form a longitudinally extending inflation channelnear one edge of the material, rows of chambers extending across thematerial, flow passageways interconnecting the chambers in each of therows, and inlet passageways extending between the inlet channel and oneof the chambers in each of the rows.

The roll rests on a pair of spaced apart, horizontally extendingrollers. The film material is fed from the roll to an inflation tubewhich extends into the inflation channel, air is introduced into thechambers through the inflation tube to inflate the cushions, and alongitudinally extending seal is formed across the passageways betweenthe channel and the chambers after the cushions are inflated.

FIG. 1 is a plan view, partly broken away, of one embodiment of aprefabricated film material for use in making air-filled packingcushions in accordance with the invention.

FIG. 2 is an isometric view of one embodiment of a machine for inflatingand sealing air-filled packing cushions in accordance with theinvention.

FIG. 3 is an exploded isometric view of the embodiment of FIG. 2.

FIG. 4 is an operational view of the embodiment of FIG. 2, illustratingthe transformation of a prefabricated film material into air-filledpacking cushions.

FIG. 5 is a fragmentary side elevational view of the sealing unit in theembodiment of FIG. 2.

FIG. 6 is a fragmentary cross-sectional view of the sealing unit of FIG.5.

FIG. 7 is a plan view of another embodiment of a prefabricated filmmaterial for use in making air-filled packing cushions in accordancewith the invention.

DETAILED DESCRIPTION

The prefabricated film material 11 shown in FIG. 1 consists of twolayers 12, 13 of a suitable film material such as high densitypolyethylene or low density polyethylene. The material can be in theform of a flattened tubing which is joined together, or closed, alongboth of its longitudinal edges 16, 17, or it can be open along one orboth edges. In the embodiment illustrated, a single elongated sheet, orstrip, of film material is folded along its centerline to form edge 16.That edge is closed, and edge 17 is open.

The two layers of film are sealed together to form an inflation channel19 and inflatable chambers 21, 22. The channel extends longitudinallynear one edge of the material, and the chambers are arranged in pairswhich are positioned side-by-side across the material. Inlet passageways23 extend between the inflation channel and one of the chambers in eachpair, and passageways 24 interconnect the chambers. Outlet passageways25 extend between the inflation channel and the open edge 17 of thematerial.

Each row or pair of chambers forms a single cushion in the finishedproduct. These cushions and other cushions with two or moreinterconnected chambers have been found to provide better cushioning andshock absorption in some applications than cushions with just onechamber do. With the interconnected chambers, air can shift from chamberto chamber as pressure is applied to different portions of the cushion.

Transverse rows of perforations 26 extend across the tubing between thechambers of successive cushions to facilitate separation of the materialeither before or after the chambers are inflated to form the cushions.

The prefabricated film material is wound onto a cylindrical core 27 toform a roll 28 for shipment and storage.

FIG. 2 illustrates is a compact, self-contained machine for inflatingand sealing a prefabricated film material in accordance with theinvention. This machine has a relatively small cabinet 31 which isadapted to rest on a table top or other supporting surface. The cabinethas an L-shaped base 32 with an upstanding front wall 33, end walls 34,36 and a removable cover 37 for the top and rear sides of the cabinet.

A pair of spaced apart, horizontally extending rollers 39, 41 aremounted on the upper side of the cabinet for receiving the roll ofprefabricated film material. The roll rests on the rollers and is freeto rotate as the material is drawn from it. The gap between the rollersis less than the diameter of the core so that the roll will not dropbetween the rollers as it decreases in size. If desired, the axis of oneor both of the rollers can be inclined slightly, i.e., up to about 10degrees, in order to keep the roll against a stop toward one side of themachine.

Roller 39 is rotatively mounted on a stationary shaft 42 which extendsbetween end walls 34, 36 near the front the cabinet. Roller 41 consistsof two relatively short rollers 41 a, 41 b which are mounted on arotatively mounted shaft 43 to the rear of roller 39. The two rollersare positioned toward opposite sides of the machine for engagement withthe roll of film material toward the edges of the roll. A nip roller 44is mounted on shaft 43 next to roller 41 b and directly beneathinflation channel 19 in the prefabricated film. A timing disk 46 is alsomounted on shaft 43, with openings 47 which are detected optically tomonitor rotation of the roll and the removal of material from it.

A stop 49 located toward one side of the cabinet serves as a guide forpositioning the roll on the rollers. The roll is placed on the rollerswith the edge adjacent to the inflation channel abutting against thestop so that the channel and the inlet passageways will always be in thesame position regardless of the width of the roll. As noted above, oneor both of the rollers can be inclined down toward the side of thecabinet where the stop is located to help keep the roll against thestop. With one or both of the rollers inclined in this manner, they arestill substantially horizontal, and the axis of the roll is stillsubstantially parallel to the axes of the rollers. The roll can be ofany desired width, and it can even overhang the side of the cabinetopposite the stop as long as it is not so wide that the weight of theoverhang causes the roll to tip or be unstable on the rollers.

A drive mechanism 51, an inflation tube 52 and a sealing assembly 53 arecombined into a single modular unit 54 which is located toward the frontof the machine. As best seen in FIG. 3, this unit is removably mountedon the outer side of end wall 36, and projects through an opening 56 inthat wall, with an end cover 57 and a front cover 58 enclosing portionsof it.

The drive mechanism includes input rollers 61–64 and output rollers66–69 which engage the edge portion of the film material and feed itthrough the machine. The input and output rollers are arranged in dualsets for engaging the film material on opposite sides of the inflationchannel. Thus, input rollers 61, 62 and output rollers 66, 67 engage thefilm material between the inflation channel and the edge of thematerial, whereas input rollers 63, 64 and output rollers 68, 69 engageit between the channel and the chambers.

The feed rollers are driven by a motor 71 which is mounted inside thecabinet, with a drive gear on the motor shaft (not shown) driving gears72 which are affixed to the shafts on which the rollers are mounted. Thegearing is such that the output rollers rotate slightly faster than theinput rollers (e.g., an 8:7 ratio) in order to tension the film materialand maintain better control of it as it passes through the sealingassembly.

Inflation tube 52 is positioned between the inner and outer feed rollersand extends in an upward direction, curving inwardly as it does, forinsertion into the inflation channel of the film material. Air issupplied to the tube at a pressure on the order of 0.5 to 10 psig by anair pump 73 which is also mounted inside the cabinet. If desired, aregulator (not shown) can be connected between the pump and the air tubeto allow users to adjust the air pressure and, hence, the degree offirmness to which the cushions are inflated.

An enlarged bulb 52 a at the upper end of the air tube facilitatesmovement of the film material over the end portion of the tube and alsohelps to prevent air from escaping back along the tube from theinflation channel. A fitting 52 b is provided at the other end of thetube for connection to the air pump.

Sealing assembly 53 is positioned between the input and output rollersand includes a heating element 76 and a roller 77 which presses the filmmaterial against the heating element. The heating element is mounted ina stationary position, and the roller is mounted on a carriage 78. Theroller is pressed against the heating element by a cam 79 when themachine is operating, and withdrawn from the heating element by springswhen the machine is idle.

As best seen in FIGS. 4–5, the heating element comprises a stainlesssteel rod 80 of relatively small diameter which extends vertically, sothat it is parallel to the direction of film travel and perpendicular tothe axis of roller 77. Thus, the curved surfaces of the heating elementand the roller come together at a very small point, so that a givenpoint on the film material is in contact with the heating element foronly about one millisecond. With that brief contact, higher heatingelement temperatures can be used, which results in better seals than arepossible with the prior art.

Sealing assembly 53 is somewhat similar to the sealing unit shown inSer. No. 09/648,843, the disclosure of which is incorporated herein byreference. There, however, the heating element consists of a pair ofNichrome wires which are covered with Teflon tape that prevents the filmmaterial from contacting the wires directly. Consequently, the filmmaterial is not heated to as high a temperature as it is in the presentinvention where the it makes direct contact with the actual heatingelement. Also, in the unit shown in Ser. No. 09/648,843, the roller ismounted in a fixed position, and the heating element is withdrawn fromthe roller by a pneumatic actuator.

Cover 58 terminates just in front of the path traveled by the filmmaterial in passing through the feed rollers and sealing assembly, and aflange 81 which extends from the front wall of the cabinet in alignmentwith the left side of the cover terminates just to the rear of the filmpath. Guide shoes 82, 83 are mounted on the confronting edges of thecover and flange to define an access opening 84 for the film materialand to help guide the material into the feed rollers. Another guide 86is positioned toward the front of the cabinet above the air tube andfeed rollers to guide the film material toward them.

A control panel 87 is located on an inclined portion of end cover 57 tothe right of the drive module. This panel includes controls for turningthe machine on and off and for controlling various operational functionssuch as number and firmness of cushions being made.

Operation and use of the machine, and therein the method of theinvention, can best be described with reference to FIG. 6. The roll ofprefabricated film material 28 is placed on rollers 39, 41, with theinflation channel side of the roll 28 abutting against stop 49, so thatthe inflation channel 19 is aligned with nip roller 44 and inflationtube 52.

The free end of the film material is pulled down over guide 86 and ontothe inflation tube, with the tube extending into inflation channel 19.The operator continues to pull down on the material until it engages theupper feed rollers and is thereafter fed by the rollers. The air tubeserves as a guide for keeping the film material properly aligned withthe rollers, and the curvature of the tube helps to guide the materialinto the rollers.

As the film material travels along the air tube, the air injectedthrough the tube flows through passageways 23, 24 and into chambers 21,22 in the portion of the film between the roll and the tube, therebyinflating the cushions. The air is confined primarily to this portion ofthe film by constriction of the inflation channel as it passes aroundthe roll and is pinched closed by nip roller 44. Depending upon thediameter of the roll, the film material is withdrawn from the roll about90 to 180 degrees from the point where the inflation channel is pinchedclosed by the roller. With the inflation channel closed down in thismanner, the cushions are inflated more efficiently and more uniformlythan in systems where the air diffuses into substantial portions of thefilm material upstream of the filling and sealing units.

Following inflation, the film material travels through sealing assembly53 where roller 77 presses the material into direct contact with heatingelement 76. The two layers of film material are thus fused togetheralong a relatively narrow seal line 89 which extends longitudinally ofthe film material and across inlet passageways 23 to seal the chambers.

After a cushion is inflated and sealed, the film material travels past aknife (not shown) which slits open the edge of the material next to theinflation channel so the air tube can exit from the channel.

In the film material illustrated in FIG. 7, each cushion 90 has onefull-size chamber 91 and two half-size chambers 92. The full-sizechamber has four sections 93 which are positioned side-by-side acrossthe film material, with passageways 94 between them. Each half-sizechamber has three sections 96, with passageways 97 between them.

Inlet passageways 98, 99 extend laterally between a longitudinallyextending inflation channel 101 and the first section in each of thechambers, and outlet passageways 102 extend between the inflationchannel and the adjacent edge of the film material. Perforations 103 areprovided between the cushions for use in separating them.

The film material of FIG. 7 is processed into cushions in exactly thesame way as the material of FIG. 1. It is fed through the machine byfeed rollers 61–69, with inflation tube 52 extending into inflationchannel 101 to deliver air for inflating the cushions, and sealingassembly 53 forming a longitudinally extending seal across inletpassageways 98, 99 to seal the inflated cushions.

With the feed rollers and the inflation tube engaging only one edgeportion of the film material, the machine can process materials of anydesired width to make cushions having any desired number of chambers,including cushions having a single chamber that extends the full widthof the material.

It is apparent from the foregoing that a new and improved machine andmethod for inflating and sealing air-filled packing cushions have beenprovided. While only certain presently preferred embodiments have beendescribed in detail, as will be apparent to those familiar with the art,certain changes and modifications can be made without departing from thescope of the invention as defined by the following claims.

1. In a method of making air-filled packing cushions from a roll ofprefabricated film material having two layers which are sealed togetherto form a longitudinally extending channel near one edge of thematerial, a plurality of chambers to one side of the channel, and inletpassageways extending laterally between the longitudinally extendingchannel and the chambers, the steps of: resting the roll of filmmaterial on a pair of spaced apart, horizontally extending rollers;feeding the film material from the roll in a downward direction to anair injector which is positioned to direct air into the chambers;introducing air into the chambers through the injector to inflate thecushions; and forming a longitudinally extending seal across the inletpassageways after the cushions are inflated.
 2. The method of claim 1wherein the longitudinally extending channel is pinched closed by one ofthe rollers, and air is injected into the longitudinally extendingchannel in a portion of the material which has been withdrawn from theroll, with the air in the longitudinally extending channel flowingaround the roll only to the point where the channel is pinched closed bythe roller.
 3. The method of claim 2 wherein the film material iswithdrawn from the roll about 90 to 180 degrees from the point where thelongitudinally extending channel is pinched closed by the roller.
 4. Amachine for making air-filled packing cushions from a roll ofprefabricated film material having two layers which are sealed togetherto form a longitudinally extending channel near one edge of thematerial, a plurality of chambers to one side of the channel, and inletpassageways extending laterally between the longitudinally extendingchannel and the chambers, comprising: a pair of spaced apart,horizontally extending rollers on which the roll of film material rests;an air injector which is connected to a source of air, positioned belowthe rollers, and extends in an upward direction for injecting air intothe chambers to inflate the cushions; a sealing unit for forming alongitudinally extending seal across the inlet passageways after thecushions are inflated; and a feed mechanism for withdrawing the filmmaterial in a generally downward direction from the roll past the airinjector and the sealing unit.
 5. The machine of claim 4 wherein thesealing unit includes a cylindrical heating element and a wheel whichare urged together, with the axis of the heating element beingperpendicular to the axis of the wheel and the heating element beingexposed for direct contact with the film material.
 6. The machine ofclaim 5 wherein the heating element comprises a stainless steel rod. 7.The machine of claim 4 wherein the longitudinally extending channel ispinched closed by one of the rollers, and the air injector comprises aninflation tube which is positioned for injecting air into thelongitudinally extending channel in a portion of the material which hasbeen withdrawn from the roll, with the air in the longitudinallyextending channel flowing around the roll only to the point where thechannel is pinched closed by the roller.
 8. The machine of claim 7wherein the film material is withdrawn from the roll about 90 to 180degrees from the point where the longitudinally extending channel ispinched closed by the roller.
 9. The machine of claim 4 wherein the airinjector comprises an inflation tube which extends into thelongitudinally extending channel, and the feed mechanism includes dualfeed rollers positioned on opposite sides of the inflation tube forengagement with the film material on opposite sides of thelongitudinally extending channel.
 10. In a machine for inflating andsealing air-filled packing cushions: a roll of prefabricated filmmaterial having two layers which are sealed together to form alongitudinally extending channel near one edge of the material, rows ofchambers extending across the material, flow passageways interconnectingthe chambers in each of the rows, and inlet passageways extendingbetween the longitudinally extending channel and one of the chambers ineach of the rows; a pair of spaced apart, horizontally extending rollerson which the roll of film material rests; an air injector which isconnected to a source of air, positioned below the rollers, and extendsin an upward direction for injecting air into the chambers to inflatethe cushions; a sealing unit for forming a longitudinally extending sealacross the inlet passageways after the cushions are inflated; and a feedmechanism for withdrawing the film material in a generally downwarddirection from the roll past the air injector and the sealing unit. 11.The machine of claim 10 wherein the sealing unit includes a cylindricalheating element and a wheel which are urged together, with the axis ofthe heating element being perpendicular to the axis of the wheel and theheating element being exposed for direct contact with the film material.12. The machine of claim 11 wherein the heating element comprises astainless steel rod.
 13. A table-top machine for making air-filledpacking cushions from a roll of prefabricated film material having alongitudinally extending channel and a plurality of chambers whichcommunicate with the channel through laterally extending inletpassageways; a cabinet which is adapted to rest on a relatively smallhorizontal supporting surface; a pair of spaced apart, horizontallyextending rollers on the upper side of the cabinet for receiving theroll of film material in such manner that the roll rests on the rollers;a feed mechanism positioned toward the front of the cabinet forwithdrawing the film material from the roll in a downward direction; anelongate member extending in an upward direction from the feed mechanismand adapted to be received in the longitudinally extending channel ofthe film material that is withdrawn from the roll; a source of airwithin the cabinet connected to an air injector for introducing air intothe chambers to inflate the cushions; and a sealing unit for forming alongitudinally extending seal in the film material between thelongitudinally extending channel and the cushions to close the inletpassageways after the cushions have been inflated.
 14. The table-topmachine of claim 13 wherein the sealing unit includes a cylindricalheating element and a wheel which are urged together, with the axis ofthe heating element being perpendicular to the axis of the wheel and theheating element being exposed for direct contact with the film material.15. The table-top machine of claim 14 wherein the heating elementcomprises a stainless steel rod.